Sensory and Motor Mechanisms

Question 1

Sensory and Motor Mechanisms

Answer 1

Sensory receptors allow the input of variety of external stimuli, while motor mechanisms allow the organism to respond.

Question 2

sensations

Answer 2

Impulses sent to the brain from activated receptors and sensory neurons.

Question 3

perceptions

Answer 3

The interpretation of sensations by the brain

Question 4

Vision - human eye

Answer 4

structure:
1. sclera
2. choroid layer
3. retina
4. cornea
5. lens
6. ciliary body
7. suspensory ligament
8. iris
9. pupil
10. aqueous humor
11. vitreous humor
12. fovea
13. optic disc
14. optic nerve

Question 5

path of light

Answer 5

cornea, 
aqueous humor, 
pupil, 
vitreous humor, 
fovea of retina

Question 6

signal transduction - photoreceptors

Answer 6

rods - night vision, black-and-white vision

cones - color vision

Question 7

physiology of black-and-white vision

Answer 7

rods contain rhodopsin (visual pigment) consisting of retinal (light-absorbing portion of molecule synthesized from vitamin A) and opsin (another protein that affects the light-absorbing ability of the retinal). When rhodopsin absorbs light retinal and opsin dissociate from the rhodopsin. This hyperpolarizes the rod, the photoreceptor secretes less neurotransmitter. Light switches off the “dark current” of the rods.

Question 8

physiology of color vision

Answer 8

• each of the three types of cone cells (red, green, and blue) has a unique visual pigment photopsin with a different form of opsin. Other colors are perceived based on the percentages of blue, green, and red cones that are stimulated

Question 9

Pathology of the Eye

Answer 9

1. color-blindness - a sex-linked trait
2. myopia - “near-sightedness”
3. hyperopia - “far-sightedness”
4. astigmatism - unequal curvature of cornea
5. cataracts
6. glaucoma

Question 10

Hearing - human ear

Answer 10

structure:
1. pinna
2. auditory canal
3. tympanic membrane
4. ossicles (malleus, incus, stapes)
5. oval window to inner ear
6. round window (pressure)
7. auditory (Eustachian) tube
8. semicircular canals
9. cochlea
10. organ of Corti
11. auditory nerve

Question 11

Physiology of Hearing

Answer 11

hair cells associated with the tectorial membrane of the organ of Corti are stimulated by vibrations resulting in depolarization and the release of neurotransmitters.

Question 12

volume

Answer 12

determined by the amplitude of the height of the sound wave

Question 13

pitch

Answer 13

determined by the frequency of the sound wave

Question 14

Physiology of Equilibrium

Answer 14

hair cells in semicircular canals, utricle, and saccule of inner ear are stimulated when endolymph moves in response to body movement